It is clearly shown that CO uptake by the human is a slow process, primarily because of the low metabolic (thus low ventilation) rate of humans in comparison with small mammals and birds. Equally important, the loss of CO from the human body breathing normal air is a slow process during which cellular/organ damage can occur, but which can be speeded by increasing the partial pressure of oxygen.

These classic data can be replotted to give curves for specific COHb saturations, ie. 10%, 20% and 30%. This kind of plot makes it very clear that a given COHb saturation can be obtained by slow CO uptake at lower CO concentration or by rapid CO uptake at higher CO concentration. See the Coburn-Forster-Kane equation.